Investigations on room temperature dual sensitization of ZnO nanostructures towards fish quality biomarkers

We report a facile and controlled synthesis of ZnO nanostructures using hydrothermal and sol-gel synthesis routes. Morphological features such as nanoaggregates and nanospheres were observed for hydrothermal and sol-gel grown ZnO nanostructures respectively. Preferential crystal orientation was observed to be along (1 0 1) plane for both the nanostructures. Excitation dependent defect centers of the nanostructures were observed. Nanospheres showed a selective detection of dimethyl sulphide (C2H6S) at room temperature. On the other hand, ZnO nanoaggregates showed dual gas sensing properties towards ammonia (NH3) and trimethylamine (C3H9N) vapours at room temperature with a maximum sensing response of 1207 and 758 respectively. Trace level detection of below 5 ppm was observed towards NH3 and C3H9N vapour. Sensing responses of these nanostructures in different relative humidity conditions were also studied and reported. The sensors showed good stability over a period of time confirmed the suitability of the sensor for practical applications in fish quality analysis.